The present invention relates to a photographic objective having a long focal length with a fastening device for a stand or tripod.
It is known to provide on the external wall of the tube of a photographic objective having a long focal length a permanent platform with a threaded receiver for a stand or tripod. The pivoting of a camera attached to such an objective for the selection of a desired image format is possible only with the use of additional adjustable means, such as, for example, a ball-and-socket joint.
In order to avoid such an unstable configuration, it is known to mount the platform having the threaded receiver for the tripod by means of an annular element which surrounds the tube of the objective, and is rotatable on the objective. The fixing of the pivoting position desired is effected by means of at least one clamping screw or clamping piece. The disadvantage of such an arrangement resides in the deformation of the objective tube by the pressure of the clamping screw(s) or the clamping pieces and the resulting stressing of the optical element mounted in the tube.
For this reason, there are already known certain fastening devices for a stand or tripod which are fixed in predetermined locations by means of notches or detends. The locked in positions are released by means of a push button arranged on one side of the tube. The disadvantages of this arrangement is the poor, cumbersome operability of the push button.